Internal Wall Insulation (IWI) — Cold Cupboard, Damp & Mould Remediation

A built-in cupboard against an external wall was generating persistent damp and mould — the cold internal surface was sitting below dewpoint on cold days, condensing moisture out of the air and causing the tenant ongoing problems. The property is tenanted, so works needed to be coordinated directly with the tenant around their availability.

Two pre-works site visits to understand the scope properly (no blind phone quoting), combined with FLIR thermal imaging to confirm the cold surfaces and identify the worst-affected areas. The work was then specified as a full internal wall insulation (IWI) build-up using Celotex / Kingspan-equivalent rigid PIR boards — a hygrothermally aware solution sized to bring the internal surface temperature well above dewpoint.

The thermal images confirmed pronounced cold spots and cold bands on the cupboard wall, lintel and reveals — surfaces between 15.7 °C and 17.7 °C against room air of ~21 °C, which is a textbook condensation/mould risk. Two site visits before quoting also revealed the job was trickier than a single day allowed for, so the scope was honestly re-priced to two days rather than rushed.

Full IWI installation to the cold cupboard: rigid PIR insulation boards (Celotex / Kingspan equivalent) fixed to the cold wall, with airtight detailing at junctions to control vapour movement. Access to the tenanted property was arranged directly with the tenant, working around their availability. Project completed under a 1-year workmanship warranty.

A dry, warmer cupboard with the internal surface now well above dewpoint — eliminating the damp and mould source at the root. The tenant is happy with the solution, the landlord has a 1-year warranty, and the job is signed off via the verbatim MyBuilder review.